Traditionally flexible pipe is utilised to transport production fluids, exportation fluids or injection fluids such as oil and/or gas and/or water from one location to another. Flexible pipe is particularly useful in connecting a sub-sea location to a further sub-sea location or a sea level location. Flexible pipe is generally formed as a length of flexible pipe body and one or more end fittings at the ends of the pipe body. The pipe body is typically formed as a composite structure of tubular layers of material that form a fluid and pressure containing conduit. The pipe structure is flexible and allows relatively large deflections without causing bending stresses that impair the pipe's functionality over a desired lifetime. The pipe body is generally, but not necessarily, built up as a composite structure including metallic and polymer layers. Flexible pipe may be utilised as a flow line over land and/or at a sub-sea location. Flexible pipe may also be used as a jumper or riser.
A riser is an assembly of one or more segments of flexible pipe connecting a sub-sea source location to a surface station or vessel. A jumper is an assembly of flexible pipe connecting a sub-sea location to a further sub-sea location. In both instances buoyancy elements have conventionally been used at desired locations so that in use the riser or jumper assembly adopts a predetermined shape. Conventional buoyancy elements are formed as separate modules manufactured from highly buoyant material or as hollow shells which can be filled with such buoyant material. Such buoyancy modules are conventionally clamped or otherwise secured to desired positions of the flexible pipe.
From time to time it is known that due to a clamping failure buoyancy modules will move from a desired location on the flexible pipe to a non-desired location. In some instances this can lead to failure of the flexible pipe as over-bending can occur.
A still further problem associated with such buoyancy modules is that should the material or integrity of the buoyancy module fail, leading to a lack of buoyancy, a large length of flexible pipe must be recovered and replaced to overcome the failure.